Try-square.



PATENTED' JUNE 7, 1904.

' c. L. WELD..

TRY-SQUARE.

APPLIOATION FILED 0012.31, 1903.

N0 MODEL.

IN YEN a "WITNIEE'IEI .ATT m ne: 2::

UNITED STATES Patented June *7, 1904.

PATENT OEEIcE.

CHARLES LOW WELD, OF PROVIDENCE, RI IODE ISLAND, ASSIGNOR TO BROWVN & SHARPE MANUFACTURING COMPANY, OF PROVIDENCE,

RHODE ISLAND.

TRY sQuARE.

SPECIFICATION forming part of Letters Patent No.761,929, dated J une 7, 1904.

Application filed October 31, 1903. Serial No. 179,384. I (No model.)

To all whmn it may concern: 7

Be it known that 1, CHARLES Low WELD, a citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented a new and useful Improvement in Try-Squares, of which the following is a specification.

This invention has reference to an im provement in try-squares, and more particularly to an improvement in the means for'securing the blade to the head of the trysquare.

In try-squares ranging in size from two to four feet or more the blade is constructed separate from the head and secured to the head by bolts. As heretofore constructed the bolts have the usual nut-heads and can be tampered with by an ordinary wrench in the hands of unskilled or malicious workmen, the loosening of the bolts throwing the square out of true and ruining its usefulness.

The object of my invention is to improve the construction of a try-square whereby the bolts used in the construction of the square have heads so formed that a special wrench is required to tighten or loosen them, and the blade is more firmly and accurately secured to the head than has heretofore been done.

My invention consists in the peculiar and noyel construction of a try-square the head of which is formed to have a depressedportion forming a shoulder for the blade, a clampingplate in the depressed end of the head working in a groove in the blade, and operated by bolts to force the blade against the trued shoulder of the head, and bolts to fasten the blade to the depressed portion of the head, all of said bolts having pentagon heads requiring a special wrench to tighten or loosen the bolts, as will be more fully set forth hereinafter.

Figure 1 is a perspective view of a trysquare, showing my improved means for accurately and rigidly securing the blade to the head of the-square. Fig. 2 is anenlarged detail face view of the try-square, showing the ends broken away and the bolts for securing the blade to the head of the square having pentagon heads to prevent tampering with-the bolts with an ordinary wrench. Fig. 3 is an edge View of Fig. 2 looking at the depressed end of the head and showing the clampingplate for accurately holding the inner edge of the blade against the trued shoulder of the head. Fig. I is asectional view taken on line 4 I of Fig. 2, showing the depressed portion of the head forming a shoulder for the blade, the clamping-plate, the chisel edge of -which coincides with a groove in the blade,

and the bolts for operating the clampingplate and securing the blade to the depressed portion of the head; and Fig. 5 is a detail view similar to Fig. 2, showing amodified form of head for the bolts requiring a special Wrench.

In the drawings, (0 indicates the head of my improved try-square, b the blade, and c the clamping-plate. The head a has the depressed portion a, forming the shoulder a and the recess a in the depressed end of the head. The shoulder a is accurately trued to bring the blade at right angles to the head a. The blade Z) has the groove Z) and the holes 6 I) for the fastening-bolts Z1 with the pentagon heads I) b. The clamping-plate c is shaped to fit the recess a in the head a and has the lip 0', bearing against the bottom of the recess (5, the holes 0 c for the bolts 0* 0 with the pentagon heads 6* If, and the chiseledge c coinciding with the groove 6 in the blade 6. In the modified form, as shown in Fig. 5, the bolts 6 b and 0* 0 have the round heads 6'' If, with the slots 6 b, which require a special form of wrench.

In securing the blade 6 to the head a the a blade is first loosely secured to the depressed portion a of the head by the bolts 1) 6 The bolts 0 c are now tightened to bring the inner edge of the blade accurately and firmly against the trued shoulder a of the head. The lip c on the clamping-plate c acting as a fulcrum, the tightening of the bolts 0 c forces the blade Z2 inward through the chisel edge 0 of the clamping-plate 0, working in the groove b in the blade. The bolts are now tightened by a special wrench to rigidly secure the blade to the head. If by accident the square becomes out of true, it can be readily trued by the use of a special wrench, as described.

By the use of my improved construction a more accurate and rigid try-square is constructed with less liability of becoming out of true by accident or misuse than has heretofore been done.

It is evident that the bolts may have any form of head desired that will require a special form of Wrench Without materially ali'ecting the spirit of my invention.

Having thus described my invention, I claim as new and desire to secure by Letters Patent- 1. In atry-square, the head, means consisting of a clamping-plate in the head working in a slot in the blade and bolts having pentagon heads for accurately clamping the blade against a shoulder on the head at right angles to the head, the blades, and means consisting of bolts having pentagon heads to rigidly secure the blade to the head for the purpose, as described,

2. In atev-square, the combination of a head having a depressed portion in one end form ing a shoulder, and a recess in the depressed end, a blade having a longitudinal groove, a

clamping-plate in the recess in the head eoinciding with the groove in the blade, bolts having pentagon heads acting on the 1 )hide through the clamping-plate and the groove in the blade to lirmly and accurately hold the blade against the shoulder on the head, and bolts having pentagon heads to rigidly secure the blade to the head, as described.

3. In a try-square, the combination ol the head r/ having the depressed portion a, the shoulder a, and the recess u", the blade ha ing the groove 7) and the holes 7/ If, the bolls 

